The hot and cold water mixing device is formed therein with a hot water passage and a cold water passage, through which hot and cold water pass, respectively, a mixing chamber therein for mixing the introduced hot and cold water, and a mixed water passage through which the mixed water is delivered, in order to mix, in a suitable ratio, the hot and cold water supplied from a hot water supply source and a cold water supply source, respectively, and to deliver the mixed water at a desired temperature.
Further, in the predetermined positions of the water passages are built and arranged a mixing valve having an automatic temperature regulating function to automatically regulate the mixing ratio of the hot and cold water to a set temperature, an opening and closing valve for regulating the delivered amount of the mixed water, and a change-over valve for performing a changeover of the delivery for faucet and the delivery for shower.
Recently, each of these valves has been summarized in a unit as a function unit which is detachably fitted within the housing of the device in order to facilitate the assembly and maintenance of the valves.
The hot and cold water mixing device, in which a valve summarized in a unit is fitted as a valve unit within the housing of the device, is known from, for example, JPB-56(1981)-2.4147. In this example, the valve unit (thermostat mixing valve) is detachably fitted within the housing of the device, which is composed of a casting material of metal such as copper alloy.
Composing the housing of the device of a casting material is preferable in that the pressure resistance of the primary water passages such as the hot water passage, cold water passage and the like within the housing is increased and the appearance of the device as a product is made more attractive. However, it has disadvantages in that cores for the water passages must be used in casting the device, which takes much time in the manufacturing process and makes the price of the product higher and, also, the device becomes heavier in weight.
For this reason, a hot and cold water mixing device is proposed in which the housing of the device is composed of a metal pipe material and the valve units are fitted therein (for example, U.S. Pat. No. 4,381,073). In this example, since the housing of the device is composed of a metal pipe material, the housing is easy to produce and can be reduced in weight.
However, it is necessary for the primary water passages (hot water passage, cold water passage) within the housing of the device to be constituted between the inner wall of the housing of the device and the outer wall of the casing of the valve unit. Therefore, the construction of the casing of the valve unit becomes complicated, i.e., the form and size of the casing of the valve unit must be changed in correspondence to the length, diameter and the like of the housing of the device and, simultaneously, a special seal construction must be provided to constitute two and more water passages.
For such reasons, there is a problem in that arranging the standardization of the valve unit is difficult and the valve unit per se becomes larger in size.
Besides this, a further hot and cold water mixing valve is known in which the housing of the device is constituted by an outer casing and an inner casing disposed inside the outer casing, and a hot water passage formed between the outer casing and the inner casing leading to a hot water supply source (JUB-63(1988)-17903).
In this example, however, there is a problem in that since the cold water passage leading to the cold water supply source is formed within the valve unit fitted in the inner casing, the construction of the valve unit becomes complicated and, simultaneously, the standardization thereof is difficult. Moreover, since the hot water passage and the cold water passage are provided in the position where they overlap with each other, the diameter of the housing of the device becomes large.
The present invention has been made taking such points into consideration and aims at providing a hot and cold water mixing device, which allows the housing thereof to be reduced in weight and the valve unit to be standardized, and which is easily assembled.